6-(Substituted-hydroxymethylene penams)

ABSTRACT

β-Lactams having a substituted hydroxymethylene group at the position α to the lactam carbonyl group are prepared by reaction of an α-halo-β-lactam with zinc or zinc amalgam in an anhydrous aprotic medium to produce an intermediate which in situ reacts with an appropriate aldehyde or ketone. 
     Also described are noval penicillins and cephalosporins having useful antibacterial activity.

This invention relates to a novel process and to novel compoundsproduced thereby.

More specifically, this invention relates to a process for preparingβ-lactams having a substituted hyroxymethylene group at the position αto the lactam carbonyl group and to novel derivatives produced thereby.

In particular, this invention relates to a process for preparing penamand cepham derivatives.

The process aspect of this invention resides in the concept of preparingand isolating β-lactams having a substituted hydroxymethylene group atthe position α to the lactam carbonyl group by reaction of anα-halo-β-lactam wherein the halo atom is located at the position that isα to the lactam carbonyl group with zinc or zinc amalgam in an anhydrousaprotic medium to produce an "intermediate" which reacts with anappropriate aldehyde or ketone.

More specifically, the process aspect of this invention resides in theconcept of the process for the preparation and isolation of a β-lactamhaving a substituted hydroxymethylene group at the position α to thelactam carbonyl group which comprises reaction of an α-halo-β-lactamwith zinc or zinc amalgam in an anhydrous aprotic medium, in thepresence of an appropriate aldehyde or ketone, and breaking the zinccomplex by the addition of water or a buffer of pH of about 5-7. Thisprocess is accomplished without affecting the integrity of the β-lactamring system.

The process of the present invention offers a one-step synthesis from ahalo-β-lactam starting material of the desired β-lactam having asubstituted hydroxymethylene group at the position α to the lactamcarbonyl group. The only previously described synthesis for compounds ofthis type is that of DiNinno, et. al., J. Org. Chem., 42, pp. 2960-2965.The DiNinno process involves the treatment of a solution of benzyl6,6-dibromo-penicillanate with n-butyllithium or methylmagnesium bromidewith excess acetaldehyde. It is then necessary to remove the bromineusing a zinc-silver couple. The synthetic procedure described by DiNinnohas also been applid to monobromopenicillanates. However, the yieldswere either low, or unwieldy low temperature conditions were required toproduce the compound. The instant process provides good yields withsimple reaction conditions utilizing zinc or zinc amalgam.

Zinc has previously been utilized as a reagent for the replacement of ahalogen-carbon bond by a carbon-carbon bond. Usually, the halide is anα-halo ester or a vinylog of an α-halo ester. The zinc forms anintermediate with the bromoester, which reacts with the carbonylcompound to give an intermediate which may be hydrolyzed to theβ-hydroxyester, which may undergo elimination to an olefin.

The process of this invention utilizes, instead of the α-halo ester, aβ-lactam substituted at the α-position by a halogen atom. The processdescribed herein most surprisingly effects the substitution of acarbon-carbon bond for the carbon-halogen bond. That a halo-β-lactamwould react under such conditions is surprising due to the rather inertcharacteristics previously reported for such halo-β-lactams. Whileα-halo esters undergo facile reaction with an aldehyde or ketone in thepresence of phosphine, β-lactams having a halogen at the α-position areunreactive under similar conditions. Similarly, the treatment of anα-halo ester with sodium azide results in the formation of thecorresponding azide, while treatment of a halo-β-lactam under suchreaction conditions causes degradation of the β-lactam ring. Thus,treatment of a halo-β-lactam with zinc or zinc amalgam and an aldehydeand ketone resulting in the formation of the carbon-carbon bond whilepreserving the integrity of the β-lactam ring system is unobvious inview of the teachings of the art.

The halo substituent of the β-lactam utilized in the instant process maybe either chloro, bromo or iodo. The starting materials wherein thehalo-β-lactam is of the penicillin type are thus of the formula ##STR1##wherein the halo atom is chloro, bromo or iodo and the wavy lineindicates either the α- or β-stereochemical configuration at the6-position. Likewise, the starting materials wherein the halo-β-lactamis of the cephalosporin type are thus of the formula ##STR2## whereinthe halo atom is chloro, bromo or iodo and the wavy line indicateseither the α- or β-stereochemical configuration at the 7-position.Another appropriate starting material is an azetidine-2-one of theformula ##STR3## wherein the halo atom is chloro, bromo or iodo and thewavy line indicates either the α- or β-stereochemical configuration atthe 3-position, and R and R' are appropriate substituted hydrocarbongroups.

Starting materials having the appropriate 6- or 7-halo substituent maybe prepared from the appropriately substituted 6-amino- or7-amino-β-lactam by reaction of the 6-amino- or 7-amino-β-lactam withsodium nitrite under the conditions described in J. Org. Chem., 27, 2668(1962). Alternatively, these starting materials can be prepared from the6- or 7-diazo compound by reaction with the appropriate hydrogen halide.Additional methodology for their preparation is described in Flynn,"Cephalosporins and Penicillins", pp. 101-105, Academic Press (1972).

The β-lactam starting material for the process of this inventionpreferably possesses the conventional penam ring system of thepenicillins, e.g., IV ##STR4## or of the cephalosporins, e.g., V##STR5## However, also utilizable in the present process are thenumerous analogous β-lactam ring systems, such as VI, described in J.Chem. Soc. C., 2093 (1969) ##STR6## wherein the dotted lines indicatethe optional presence of a double bond; such as VII, described in Can.J. Chem. 55, 468 (1977), Can. J. Chem. 55, 484 (1977) and Belgian Pat.Nos. 850,779 and 850,593 ##STR7## wherein X is sulfur or oxygen; such asVIII, described in U.S. Pat. Nos. 4,068,075, 4,068,078, and 4,068,080##STR8## wherein X is nitrogen, sulfur or oxygen; such as IX and X,described in Recent Advances in the Chemistry of β-Lactam Antibiotics,Special Publication No. 28, Chapter 28, p. 213 (1977), ##STR9## such asXI, ##STR10## such as XII, described in J. Amer. Chem. Soc. 88, 852(1966), ##STR11## such as XIII, described in J. Amer. Chem. Soc. 88, 852(1966), ##STR12## and those such as XIV, ##STR13## wherein X isnitrogen, oxygen or sulfur and R is alcohol, acyl ester, cyanide,sulfur, S--CH₃, nitrogen function or halogen.

Preferred starting materials for use in the reaction of this inventionare: 6-halopenicillanic acid esters of the formula ##STR14## whereinhalo is a halogen selected from the group consisting of chlorine,bromine or iodine, R₃ is hydrogen or lower alkoxy, and R₄ is cyano orCOOR₁₁ wherein R₁₁ is a readily removable ester-forming moiety;

7-halocephalosporanic acid esters of the formula ##STR15## wherein halo,R₃ and R₁₁ are as hereinbefore defined, R₅ is hydrogen, loweralkanoyloxy, lower alkoxy, lower alkylthio, pyridinium, ##STR16##wherein R₆, R₇ and R₈ are hydrogen, lower alkyl, phenyl, loweralkylphenyl, halophenyl, hydroxyphenyl, lower alkoxyphenyl, or ##STR17##wherein R₉ and R₁₀ can be the same or different and are hydrogen orlower alkyl;

6-halopenicillanic acid esters of the formula ##STR18## wherein halo andR₁₁ are as hereinbefore defined, ##STR19## is an attached keto oraldehyde functional group, R₂ is a group of the formula

    --(CH.sub.2).sub.m --X.sub.p --(CH.sub.2).sub.n --

wherein X is O or S; m is 0-3; n is 0-3; p is 0-1; with the proviso thatm+n+p is 3-5; ##STR20## wherein halo, R₉, R₁₀ and R₁₁ are ashereinbefore defined; and ##STR21## wherein halo and R₁₁ are ashereinfore defined.

The process of this invention involves reacting the halo-β-lactam withzinc or zinc amalgam to form a zinc-halo-β-lactam intermediate whichgoes on to react with aldehyde or ketone to form the fnal isolatableproduct.

This type of process is represented schematically as follows: ##STR22##wherein ##STR23## is the aldehyde or ketone and halo is chloro, bromo oriodo.

This process also proceeds when the aldehyde or ketone is part of themolecule reacted with the zinc or zinc amalgam resulting in anintramolecular reaction. This may be schematically represented by thefollowing diagram: ##STR24## wherein ##STR25## is an attached keto oraldehydo functional group, R₂ is a group of the formula

    --(CH.sub.2).sub.m --X.sub.p --(CH.sub.2).sub.n --

wherein X is O or S; m is 0-3; n is 0-3; p is 0-1; with the proviso thatm+n+p is 3-5; and halo is chloro, bromo or iodo.

The process is preferably carried out under an inert atmosphere, e.g.,nitrogen or argon to prevent undesirable side reactions. Atmosphericpressure affords reasonable reaction time for the process. However,pressure is generally not relevant except for gaseous aldehydes.

The process is necessarily carried out under anhydrous conditions toavoid conversion of the zinc-halo-β-lactam intermediate to thedehalo-β-lactam.

Solvents suitable for use in this process are any polar or non-polaraprotic organic solvent in which the halo-β-lactam starting material issoluble. Particularly useful solvents for the process are ethers such asethyl ether, tetrahydrofuran, dioxane and diglyme; aromatic hydrocarbonssuch as benzene, toluene, xylene; and tertiary amides such asdimethylformamide and diethylformamide. Benzene and tetrahydrofuran areespecially preferred solvents.

A solvent is not strictly necessary for the operation of the process ofthis invention, although its use is generally preferred. Thus, in thecase where the aldehyde or ketone is a liquid in which the halo-β-lactamis soluble, the halo-β-lactam in the liquid aldehyde or ketone may bereacted with zinc or zinc dust without a solvent.

The reactions of this process are generally carried out at temperaturesin the range of from about 0° C. to about 110° C. The reaction can alsobe carried out at the reflux temperature of the solvent used, with careto avoid temperatures above the boiling points of the aldehyde or ketonereactant. The reaction time depends upon the halo-β-lactam employed andthe temperature at which the reaction is conducted. Reaction times of2-12 hours are typical.

The zinc or zinc amalgam utilized in the process of this invention isactivated in a conventional manner prior to its use in the reaction.Typical methods for accomplishing the activation may be found byreference to the following: Fieser and Fieser, Reagents for OrganicSynthesis, Vol. 1, p.. 1269 (1967); Chem. Communications, 269 (1973);Synthesis, 452 (1975) and "Accounts of Chemical Research", Vol. 10, 301(1977).

The aldehydes and ketones utilizable in the present invention are thosecontaining no functional group that would preferentially react with zincor a zinc-halo-β-lactam intermediate over their oxo functionality, arenot self-reacting, and do not generate a proton source substituent.Thus, aldehydes and ketones containing an unprotected hydroxy or aminogroup are not utilizable as such in this invention. The aldehydes andketones may, however, contain these groups if the groups are suitablyprotected, e.g., with benzyl, benzhydryl, or tetrahydropyranyl groups,prior to reaction. Illustrative of groups that the aldehyde or ketonemay contain are aliphatic groups of 1 to 20 carbon atoms, unsaturatedstraight- or branched-chain carbon groups of 1 to 20 carbon atoms,cycloalkyl groups of four to seven carbon atoms, heterocyclic groups nothaving fee protons, e.g., tetrahydrofuran and thiophene groups, etc.

The halo-β-lactam starting materials must also be devoid of a protonsource. Thus, for carboxy-, amino- and hydroxy-substituted compounds tobe utilized in the process, the carboxy-, amino- and/orhydroxy-functional group must be protected from reaction by means of asuitable protecting group, e.g., benzyl r benzyloxy. Such groups ascyano, alkyl, and alkoxy are stable to the reaction conditions and thusmay be present in the halo-β-lactam molecule without protecting groups.

A compound aspect of this invention resides in the concept of certainhydroxyalkyl-β-lactams and particularly the hydroxycycloalkyl-β-lactamswhich exhibit useful antibacterial activity. Most particularly, thisaspect relates to compounds of the formulae: ##STR26## wherein Y is anitrogen, optionally lower alkyl, aryl or lower alkanoyl-substituted,

oxygen,

sulfur,

oxygenated sulfur, or a lower alkyl, lower alkanoyl,

or aryl-substituted or unsubstituted methylene group;

Z is selected from the group consisting of: ##STR27## wherein the dottedlines indicate optional double bonds; R₅ is hydrogen,

lower alkanoyloxy,

lower alkoxy,

lower alkylthio,

pyridinium,

cyano, ##STR28## wherein R₆, R₇, and R₈ are hydrogen,

lower alkyl,

phenyl,

lower alkylphenyl,

halophenyl,

hydroxyphenyl,

lower alkoxyphenyl, or ##STR29## wherein R₉ and R₁₀ can be the same ordifferent and are hydrogen, or lower alkyl;

R and R₁ together with the carbon atom to which they are attached, isthe carbon residue of an aldehyde or ketone which contains no functionalgroup that would preferentially react with a zinc halo-β-lactamintermediate over the oxo functionality; R₂ is a group of the formula

    --(CH.sub.2).sub.m --(X).sub.p --(CH.sub.2).sub.n --

wherein

X is O or S;

m is 0-3;

p is 0-1;

n is 0-3; and

m+p+n is 3-5;

R₃ is hydrogen or lower alkoxy; and

R₄ is cyano, or --COOR₁₁ wherein R₁₁ is a readily removableester-forming moiety, with the proviso that when R₃ is hydrogen, R₄ is--COOR₁₁, R₁₁ is benzyl or t-butyl, Y is nitrogen, and Z is ##STR30##then R and R₁ together with the carbon atom to which they are attached,cannot be an acetaldehyde residue, and the pharmaceutically acceptableacid addition salts thereof.

These compounds are produced directly by the process of this invention.

Especially preferred compounds of formulae (XX) and (XXI) are thosewherein Y is sulfur, Z is ##STR31## wherein R₅ is hydrogen, and R₄ iscyano. Reaction of the 6-bromo starting materials with various aldehydesand particularly substituted benzaldehydes produces compounds having aparticularly desirable spectrum of antibacterial activity.

A further compound aspect of this invention relates to the preparationof compounds of the formulae: ##STR32## wherein R, R₁, R₂, R₃, Y and Zare as hereinbefore defined; R₁₂ is hydroxy, lower alkoxy, formyloxy,lower alkanoyloxy, lower alkylsulfonyloxy, or a halogen atom; and R₁₃ ishydrogen, an alkali metal cation, acetoxymethyl, or a readily removableester-forming moiety with the proviso that when R₁₂ is hydroxy, then R₁₃is not a readily removable ester-forming moiety, and thepharmaceutically acceptable acid addition salts thereof.

The lower alkyl groups referred to above contain 1 to 6 carbon atoms andare exemplified by methyl, ethyl, propyl, butyl, pentyl, hexyl, and thecorresponding branched-chain isomers thereof.

The lower alkoxy groups referred to above likewise contain 1 to 6 carbonatoms and are exemplified by methoxy, ethoxy, propoxy, and the like.

Similarly, the lower alkanoyloxy groups contain from 2 to 7 carbon atomsand are typified by such groups as acetyloxy, propionyloxy and thecorresponding branched-chain isomers thereof.

The "halogen atoms" encompassed by the term as used in this inventionencompass fluorine, chlorine, bromine or iodine unless otherwisespecified.

The term "lower alkylthio" refers to lower alkyl substituted thio groupssuch as methylthio, ethylthio, n-propylthio, isopropylthio, and thelike.

"Lower alkylphenyl" likewise refers to phenyl groups substituted by oneor two alkyl groups containing 1 to 6 carbon atoms. The term encompassessuch groups as methylphenyl, ethylphenyl, n-propylphenyl,isopropylphenyl, dimethylphenyl, methylethylphenyl, and the like.

As used herein, the term "halophenyl" refers to mono- anddihalosubstituted phenyl groups such as mono- and dichlorophenyl, mono-and difluorophenyl and mono- and dibromophenyl groups.

The term "aryl" as used herein refers to phenyl substituted by one ormore substituent groups selected from among chloro, bromo, fluoro, loweralkyl, hydroxy, nitro, amino, aminomethyl, lower monoalkylamino, lowerdialkylamino, lower alkoxy and carboxy. Such aryl groups represented byR₁ can be, for example, 4-hydroxyphenyl, 3,4-dichlorophenyl,2,6-dimethoxyphenyl, 4-methylphenyl, 2-fluorophenyl, 4-carboxyphenyl,3-nitrophenyl, 4-aminophenyl, 3-aminophenyl, 4-dimethylaminophenyl,4-aminomethylphenyl and 4-ethoxyphenyl.

The term "readily removable ester-forming moiety" refers to the commonlyemployed carboxylic acid protecting groups employed for protecting theC₃ carboxylic acid group of the penicillins and the C₄ carboxylic acidgroup of the cephalosporins. Representative of such groups are t-butyl,benzyl, benzhydryl, p-nitrobenzyl, 4-methoxybenzyl, 3,5-dimethoxybenzylor tetrahydropyranyl and like cleavable ester moieties.

The compounds wherein R₁₃ is hydrogen are produced from thecorresponding compounds wherein R₁₃ is a readily removable ester-formingmoiety. A convenient method for accomplishing this reaction is byhydrogenation of the compound wherein R₁₃ is a readily removableester-forming moiety sensitive to reductive cleavage in the presence ofa palladium or palladium-on-carbon catalyst. Typical times are in therange of 6-48 hours and typical pressures in the range of atmospheric to60 psi. For example, benzyl 6β-(α-hydroxy-o-fluorobenzyl)penicillanateis converted to 6β-(α-hydroxy-o-fluorobenzyl)penicillanic acid byhydrogenation for 40 hours at atmospheric pressure in the presence of a30% palladium-on-carbon catalyst.

The compounds wherein R₁₃ is an alkali metal cation are produced fromthe corresponding compounds wherein R₁₃ is hydrogen by contact with oneequivalent of an alkali metal salt in water at room temperature. Forinstance, 6β-(1-hydroxyethyl)penicillanic acid is converted to thecorresponding sodium salt by treatment with 1 equivalent of sodiumbicarbonate in water.

The compounds wherein R₁₂ is formyloxy or lower alkanoyloxy are producedfrom the corresponding compounds wherein R₁₂ is hydroxy. Theesterification proceeds conventionally utilizing an appropriate acidchloride, acid anhydride or activated amide in the presence of an acidacceptor. The acid acceptor may be an organic base such as pyridine ortriethylamine or an inorganic base such as sodium or potassiumhydroxide, or sodium or potassium bicarbonate. For instance,6-(1-hydroxyethyl)penicillanate may be converted to6-(1-formyloxyethyl)penicillanate using dimethylformamide and tosylchlorides or methanesulfonyl chloride; or to6-(1-acetoxyethyl)penicillanate using acetic anhydride or acetylchlorideand pyridine.

The compounds wherein R₁₂ is lower alkylsulfonoxy are produced from thecorresponding compounds wherein R₁₂ is hydroxy and R₁₃ is a readilyremoved ester-forming moiety, by contacting with the appropriatealkylsulfonyl halide or alkylsulfonic anhydride in the presence of anacid acceptor. The R₁₃ group may then be removed as describedhereinbefore.

The compounds wherein R₁₂ is halogen are prepared from the correspondingcompounds wherein R₁₂ is an alkanesulfonyloxy group, preferablymethanesulfonyloxy, and R₁₃ is a readily removable ester-forming moietyby contact with the appropriate halide ion. For instance, sodium iodidemay be used to convert benzhydryl6-(1-methanesulfonyloxyethyl)-penicillanate to the correspondingbenzhydryl 6-(1-iodoethyl)penicillanate. The R₁₃ protecting group may beoptionally be removed as hereinbefore described (other than byhydrogenation) to afford the corresponding free acid, i.e.,6-(1-iodoethyl)penicillanic acid.

The double bond of the cephem system may be isomerized by base to afforda mixture of the Δ² and Δ³ cephems as products. The mixture is thenseparated by chromatography to afford the desired Δ³ compounds in a purestate.

Alternatively, the mixture is first oxidized to the sulfoxide accordingto the method of O'Connor and Lyness, J. Amer. Chem. Soc. 86, 3840(1964). The sulfoxide is then reduced in the presence of an activatingagent according to the method of Kaiser, et. al., J. Org. Chem. 35, 2430(1970) to afford the Δ³ compounds in their pure state.

The compounds produced by the process of this invention possessantibacterial activity. Additionally, they are penicillinase inhibitorswhich may be used concommitantly with other penicillin-type antibioticsin infection therapy.

Thus, when tested in standardized microbiological assays the compoundsof this invention exhibit activity vis-a-vis such organisms asStaphylococcus epidermidus, Salmonella, Bacillus subtilis, andPseudomonas aeruginosa at test levels of 0.1 to 100 μcg/ml.Additionally, they show activity against such organisms in the presenceof penicillanase and cephalosporinase indicating a resistance to theseenzymes. For instance,6β-(p-benzyloxy-α-hydroxybenzyl)-2,2-dimethyl-3α-cyanopenam and6α-(p-benzyloxy-α-hydroxybenzyl)-2,2-dimethyl-3α-cyanopenam showactivity vis-a-vis S. epidermidis and B. subtilis at levels of 0.25 to16 μcg/ml. The by-product, 2,2-dimethyl-3α-cyanopenam, exhibits activityvis-a-vis S. epidermidis (containing penicillanase) and B. subtilis(containing cephalosporinase) at levels of 0.1 to 50 μcg/ml.Additionally, this compound is a competitive β-lactamase inhibitor.Thus, as antibacterial agents these compounds are conventionallyformulated for oral, intramuscular and intravenous therapy.

Thus, the present invention includes within its scope pharmaceuticalcompositions comprising the novel β-lactams of this invention with acompatible pharmaceutical carrier therefor.

The dosage administered of the β-lactams of this invention is dependentupon the age and weight of the animal species being treated, the mode ofadministration, and the type and severity of bacterial infection beingprevented or reduced. Typically, the dosage administered per day will bein the range of 100-5000 mg with 500-1000 mg being preferred.

For oral administration, the compounds of this invention may beformulated in the form of tablets, capsules, elixirs or the like. Forparenteral administration they may be formulated into solutions orsuspensions for intramuscular injection.

The following examples describe in detail the process of the presentinvention and the compounds produced therefrom. It will be apparent tothose skilled in the art that many modifications, both of materials andmethods, may be practiced without departing from the spirit and scope ofthe invention.

PREPARATION 1

A solution of 11.0 g of benzyl 6-diazopenicillanate 1β-oxide and 9 g3-buten-1-ol in 120 ml dichloromethane is stirred with ice-cooling, and7.5 g N-bromosuccinimide is added in portions over a 5 minute period.After stirring for 18 minutes at room temperature, the solution iswashed successively with water, aqueous sodium sulfite and aqueoussodium bicarbonate. After drying over anhydrous magnesium sulfate andremoval of the solvents in vacuo, the residue is chromatographed onsilica gel by eluting rapidly with benzene followed by 10% ethyl acetatein benzene. The product, benzyl6α-(3-buten-1-yloxy)-6β-bromopenicillanate 1β-oxide, is isolated as ayellow oil. This compound is represented by the formula: ##STR33##

PREPARATION 2

A solution of 9.2 g benzyl 6α-(3-buten-1-yloxy)-6β-bromopenicillanate1β-oxide in 70 ml dry dimethylformamide is cooled to 5° C. Then, 2.4 mlphosphorus tribromide is added dropwise and the mixture is stirred for 1hour at room temperature. The mixture is added to ice water andextracted with ethyl ether. The organic phase is separated and washedsuccessively with water, sodium bicarbonate solution and saturatedsodium chloride solution. After drying over anhydrous magnesium sulfate,the solvents are removed by evaporation. The crude product ischromatographed rapidly on 150 g silica gel using 1:1dichloromethane-hexane as the eluant, affording benzyl6β-bromo-6α-(3-buten-1-yloxy)penicillanate, as a yellow oil, and havingthe following formula: ##STR34##

PREPARATION 3

A solution of 6.3 g benzyl 6β-bromo-6α-(3-buten-1-yloxy)penicillanate in80 ml dichloromethane and 30 ml methanol is cooled to -20° C. andozonized oxygen is introduced until the starting material is consumed(as determined by t.l.c.). Then, 10 ml dimethyl sulfide is added, theresultant solution is brought to room temperature, and washed twice with100 ml portions of water. The aqueous phases are combined and extractedwith 50 ml dichloromethane. The dichloromethane extracts are combinedwith the original organic phase and dried over anhydrous magnesiumsulfate. The dried solution is evaporated in vacuo at room temperatureto leave benzyl 6α-(3-oxopropoxy)-6β-bromo-penicillanate as an oil.

EXAMPLE 1

To a solution of 500 mg methyl 6α-bromopenicillanate in 7 ml anhydrousacetaldehyde is added active zinc dust with constant stirring at 20° C.The progress of the reaction is monitored by thin layer chromatographyusing a 10% acetone in benzene solvent system. Upon completion of thereaction, the zinc is removed by filtration, and the mixture is dilutedwith 50 ml ethyl acetate and washed with phosphate buffer (10 ml) of pH5 to remove the zinc salts. After drying the solution over anhydroussodium sulfate and removing the solvent under vacuum, the product ischromatographed through silica using 3% acetone in benzene as eluant.The initial fraction is discarded. The following fractions afford, in80:20 ratio, methyl 6β-(1-hydroxyethyl)penicillanate and methyl6α-(1-hydroxyethyl)penicillanate. The 6β compound has the followingformula: ##STR35##

EXAMPLE 2

A solution of 500 mg methyl 6-bromopenicillanate in 25 ml dry benzenecontaining 1 ml benzaldehyde and 2 g active zinc dust is refluxed undera nitrogen atmosphere with vigorous stirring for approximately 6 hours.Upon termination of the refluxing, the reaction mixture is diluted, with50 ml ethyl acetate and washed with a phosphate buffer of pH 5. Thesolution is dried over anhydrous sodium sulfate and the solvents areremoved under vacuum. The products were separated by preparation thinlayer chromatography using multiple elutions with 3% acetone inchloroform to afford, in a 6:1 ratio, methyl6α-(α-hydroxybenzyl)penicillanate and methyl6β-(α-hydroxybenzyl)penicillanate.

EXAMPLE 3

To a solution of 8 g benzhydryl 6α-bromopenicillanate in 150 ml drytetrahydrofuran is added 35 ml dry acetaldehyde, followed by 13 g activezinc. The mixture is then stirred very vigorously for 21/2 hours. Uponcompletion of the reaction, the mixture is taken up in 500 ml ethylether and washed with phosphate buffer of pH 5. The solution is driedover anhydrous sodium sulfate and the solvents are removed under vacuum.The resultant foamy solid is chromatographed through silica gel using 5%acetone in benzene to afford a major amount of benzhydryl6β-(1-hydroxyethyl)penicillanate and a minor amount of benzhydryl6α-(1-hydroxyethyl)penicillanate.

EXAMPLE 4

To a solution of 1.5 g benzhydryl 6α-bromopenicillanate in 20 ml drytetrahydrofuran is added 3 ml o-fluorobenzaldehyde, followed by 2.5 gactive zinc. After stirring vigorously for 4 hours, the zinc is filteredfrom reaction mixture and the mixture is taken up in 200 ml ethylacetate and washed first with phosphate buffer of pH 5 and then with 15ml of 1% aqueous sodium bicarbonate. After drying the solution overanhydrous sodium sulfate and removal of the solvents under vacuum, theproduct is chromatographed utilizing 5% acetone in toluene to affordbenzhydryl 6β-(o-fluoro-α-hydroxybenzyl)penicillanate and benzhydryl6α-(o-fluoro-α-hydroxybenzyl)penicillanate. The 6β compound has thefollowing formula: ##STR36## When p-dimethylaminobenzaldehyde issubstituted for the o-fluorobenzaldehyde in the above procedure, thereis obtained benzhydryl 6-(p-dimethylamino-α-hydroxybenzyl)penicillanate.

EXAMPLE 5

To a solution of 2.5 g benzhydryl 6α-bromopenicillanate in 35 ml drytetrahydrofuran is added 5 ml cinnamaldehyde and 5.2 g active zinc. Theresultant solution is stirred vigorously for 12 hours in the presence ofa catalytic amount of copper (II) chloride. The mixture is then taken upin 200 ml ethyl acetate and washed with phosphate buffer of pH 5. Thesolution is dried over anhydrous sodium sulfate and the solvents removedunder vacuum. The excess cinnamaldehyde is removed by using high vacuumand the product is chromatographed using 5% acetone in benzene to affordbenzhydryl 6β-(1-hydroxy-3-phenylprop-2-enyl)penicillanate andbenzhydryl 6α-(1-hydroxy-3-phenylprop-2-enyl)penicillanate. The 6βcompound has the formula: ##STR37##

EXAMPLE 6

A solution of 1 g of benzyl 7α-bromo-3-methylenecephalosporinate in 50ml dry tetrahydrofuran is stirred with 5 ml dry acetaldehyde and 5 gactive zinc under a nitrogen atmosphere for 1.5 hours. The reactionmixture is then filtered, diluted with 100 ml ethyl acetate and washedwith phosphate buffer of pH 5. The solution is dried over anhydroussodium sulfate and the solvents removed under vacuum. NMR spectra showthat the exocyclic methylene group is intact. Chromatography on thinlayer chromatography plates using 5% acetone in benzene affords benzyl7β-(1-hydroxyethyl)-3-methylenecephalosporinate and benzyl7α-(1-hydroxyethyl)-3-methylenecephalosporinate. Each of the twocompounds is then independently treated with 500 mg triethylamine in 20ml ethyl acetate to shift the double bond to conjugation. The solventsare removed under high vacuum to afford, respectively, benzyl7β-(1-hydroxyethyl)desacetoxy-Δ² or Δ³ -cephalosporinate and benzyl7α-(1-hydroxyethyl)desacetoxy-Δ² or Δ³ -cephalosporinate.

EXAMPLE 7

A solution of 1.6 g benzhydryl 7α-bromocephalosporinate in 50 ml drytetrahydrofuran is stirred with 3.2 g active zinc dust and 8 mlacetaldehyde for 20 hours. The reaction mixture is then filtered,diluted with ethyl acetate and washed with phosphate buffer of pH 5. Thesolution is dried over anhydrous sodium sulfate and the solvents areremoved under vacuum. Chromatography of the resultant product affordsbenzhydryl 7β- and 7α-(1-hydroxyethyl)cephalosporinate as well as thecorresponding 7β- and 7α-Δ² compounds.

EXAMPLE 8

To a solution of 3.0 g benzyl 6β-bromo-6α-methoxypenicillanate in 35 mldry tetrahydrofuran and 10 ml dry acetaldehyde is added 2 g zinc dust.The mixture is stirred at 25° C. under a nitrogen atmosphere for 2hours. The excess zinc is removed by filtration and washed with ethylacetate and the filtrates washed first with dilute hydrochloric acid andthen sodium bicarbonate solution. After drying over anhydrous magnesiumsulfate, the solvents are removed in vacuo and the residuechromatographed on silica gel, eluting with chloroform containing 0.5%methanol. The appropriate fractions containing the desired product(F_(f) ≃0.5 on silica gel in 1% methanol-chloroform) are combined andrechromatographed on silica using 7% ethyl acetate in benzene. Removalof the solvents and recrystallization from ether-hexane give the desiredproduct, benzyl 6-(1-hydroxyethyl)-6-methoxypenicillanate, as a whitesolid melting at 86°-88° C. and having the following formula: ##STR38##wherein the wavy lines indicate the α- or β-configuration.

EXAMPLE 9

To a solution of 0.3 g 2,2-dimethyl-3α-cyano-6α-bromopenam in 6 mlanhydrous tetrahydrofuran and 1.68 ml anhydrous acetaldehyde is added1.0 active zinc dust. The reaction mixture is stirred vigorously at roomtemperature for 4 hours where upon 1 ml phosphate buffer of pH 5 isadded. After stirring a few minutes, the reaction mixture is dilutedwith ethyl acetate, filtered and the organic phase washed once withbrine. After drying over anhydrous sodium sulfate, the residue ischromatographed on silica gel, using 3% acetone in benzene as eluant.Thus isolated, in a 2:1 ratio, are2,2-dimethyl-3α-cyano-6β-(1-hydroxyethyl)penam and2,2-dimethyl-3α-cyano-6α-(1-hydroxyethyl)penam.

A by-product of this reaction, 2,2-dimethyl-3α-cyanopenam, is alsoisolated in a minor amount.

EXAMPLE 10

To a solution of 60 mg 2,2-dimethyl-3α-cyano-6α-bromopenam and 3 dropsbenzaldehyde in 1 ml dry tetrahydrofuran is added 1 g zinc dust. Thereaction mixture is stirred at room temperature for about 12 hours undernitrogen atmosphere. A few drops of phosphate buffer of pH 5 is addedand then the mixture is diluted with ethyl acetate. The zinc dust isfiltered and washed with ethyl acetate. The ethyl acetate extracts arecombined, washed with aqueous sodium chloride, and dried over anhydroussodium sulfate. Chromatography of the mixture on silica gel using 10%acetone in chloroform affords in an 11:6 ratio,2,2-dimethyl-3α-cyano-6α-(α-hydroxybenzyl)penam and2,2-dimethyl-3α-cyano-6β-(α-hydroxybenzyl)penam.

EXAMPLE 11

A solution of 100 mg 2,2-dimethyl-3α-cyano-6α-bromopenam in 40 ml drytetrahydrofuran is stirred with 60 mg p-dimethylaminobenzaldehyde and500 mg zinc for about 12 hours at room temperature. The reaction mixtureis then diluted in ethyl acetate, washed with aqueous sodium chlorideand dried over anhydrous sodium sulfate. Chromatography of the mixtureon silica gel affords, in 11:1 ratio,2,2-dimethyl-3α-cyano-6α-(p-dimethylamino-α-hydroxybenzyl)penam and2,2-dimethyl-3α-cyano-6β-(p-dimethylamino-α-hydroxybenzyl)penam. The6α-compound has the following formula: ##STR39## Utilizing7α-bromo-4-cyano-3-cephem in the above procedure similarly affords7α-(p-dimethylamino-α-hydroxybenzyl)-4-cyano-3-cephem.

EXAMPLE 12

Utilizing substantially the procedure detailed in Example 11,2,2-dimethyl-3α-cyano-6α-bromopenam is reacted withp-benzyloxybenzaldehyde to afford2,2-dimethyl-3α-cyano-6α-(p-benzyloxy-α-hydroxybenzyl)penam and2,2-dimethyl-3α-cyano-6β-(p-benzyloxy-α-hydroxybenzyl)penam. Thesecompounds are represented by the following structural formula whereinthe wavy line represents the α- or β-configuration. ##STR40##

EXAMPLE 13

A solution of 5.8 g benzyl 6α-(3-oxopropoxy)-6β-bromopenicillanate in100 ml dry tetrahydrofuran is stirred under argon for 20 hours with 25 gzinc dust. The mixture is then diluted with 200 ml ethyl acetate and 10ml water, and the solids filtered and washed with ethyl acetate. Thefiltrate is washed with water, dried over anhydrous magnesium sulfateand evaporated. The residue is chromatographed on 80 g silica geleluting rapidly with dichloromethane followed by 5% ethyl acetate indichloromethane. The appropriate eluates are combined and evaporated togive a mixture of benzyl spiro-[3'-hydroxyoxacyclopentyl]-2',6α-penicillanate and benzyl spiro[3'-hydroxyoxacyclopentyl]-2',6β-penicillanate.

Separation is effected by preparative thin layer chromatography on 0.1cm layer plates, using two elutions with 3:2 v/v hexane:ethyl acetate.The bands are removed, the products are eluted using ethyl acetate.After evaporation, the residues are recrystallized from ether-hexane toafford the two compounds as white prisms, m.p. 105°-106° C. and as whiteprisms melting at 113°-115° C. These may be represented by the formula##STR41## wherein the wavy line indicates the α- or β-configuration.

EXAMPLE 14

A solution of 150 mg of benzhydryl 6β-(1-hydroxyethyl) penicillanate in25 ml ethanol is hydrogenolysed in the presence of a 10%palladium-on-carbon catalyst at 20 psi. After 24 hours, the solution isfiltered to remove the catalyst and the solvent is evaporated. Theresultant crystals, 6β-(1-hydroxyethyl)penicillanic acid, are treatedwith one equivalent of sodium bicarbonate in water. Freeze drying thusaffords sodium 6β-(1-hydroxyethyl)penicillanate.

EXAMPLE 15

A solution of 100 mg benzyl 7-(1-hydroxyethyl) desacetoxy-Δ³-cephalosporinate in 20 ml ethanol is hydrogenated at 30 psi using a 10%palladium-on-carbon catalyst for 30 hours. The reaction mixture is thenfiltered to remove the catalyst and the solvent removed under vacuum toafford 7-(1-hydroxyethyl) desacetoxy-Δ³ -cephalosporanic acid. Thisproduct is then treated with one equivalent of sodium bicarbonate andlyophilized to yield sodium 7-(1-hydroxyethyl)desacetoxy-Δ³-cephalosporanic acid having the following structural formula ##STR42##wherein the wavy line indicates the α- or β-configuration.

EXAMPLE 16

A solution of 38 mg of benzhydryl6β-(o-fluoro-α-hydroxybenzyl)penicillanate in 10 ml ethanol containing 2mg N-methylglucamine is hydrogenated for 40 hours using a 30%palladium-on-carbon catalyst and atmospheric pressure. The reactionmixture is then filtered, the solvent removed under vacuum, and theresultant product washed with petroleum ether to remove any excessdiphenylmethane. Thus produced is6β-(o-fluoro-α-hydroxybenzyl)penicillanic acid.

EXAMPLE 17

A solution of 150 mg benzhydryl 6-(1-hydroxyethyl) penicillanate in 5 mldry dimethylformamide is treated with 200 mg tosyl chloride followed by200 mg triethylamine. After 12 hours, the reaction mixture is dissolvedin ethyl acetate and then washed successively with water, 5% aqueousphosphoric acid, 1% aqueous sodium bicarbonate, and brine. After thesolution is dried over anhydrous sodium sulfate, the solvents areremoved under vacuum to afford, as a foam, benzhydryl6-(1-formyloxyethyl)penicillanate.

EXAMPLE 18

A solution of 411 mg benzhydryl 6-(1-hydroxyethyl) penicillanate in 10ml dry acetonitrile is treated with 150 mg dry pyridine and 250 mgmethanesulfonic anhydride. When the starting material is no longerpresent (as determined by thin layer chromatography), the reactionmixture is diluted with 50 ml ethyl acetate and washed first with 3 mlof 5% aqueous phosphoric acid, subsequently with 15 ml of 2% aqueoussodium bicarbonate and finally with brine. The resultant solution isdried over anhydrous sodium sulfate and the solvents removed undervacuum to afford as a foamy solid, benzhydryl6-(1-methanesulfonyloxyethyl)-penicillanate.

EXAMPLE 19

A solution of 50 mg of benzhydryl6-(1-methanesulfonyloxyethyl)penicillanate in 5 ml dry acetone is keptin the presence of 200 mg sodium iodide for 5 days. The acetone is thenremoved under vacuum and the residue is dissolved in 50 ml ethyl ether.The ether solution is washed first with water and then with aqueoussodium thiosulfate. After drying over anhydrous sodium sulfate, thesolvent is removed under vacuum to afford, as a while solid, benzhydryl6-(1-iodoethyl)penicillanate, having the formula ##STR43##

EXAMPLE 20

A solution of 0.6 g benzyl 6-(1-hydroxyethyl)-6-methoxypenicillanate in30 ml ethanol and 10 ml water containing 0.2 g sodium bicarbonate isshaken for 20 hours with 1 g 10% palladium-on-charcoal catalyst at 60psi. The mixture is then filtered, washed with aqueous ethanol andevaporated in vacuo to remove most of the ethanol. The residual aqueoussolution is extracted once with ether and the extract discarded. Theaqueous phase is acidified to about pH 1.5 with phosphoric acid and thenextracted 5 times with 50 ml portions of dichloromethane. Thedichloromethane extracts are combined, dried over anhydrous magnesiumsulfate and evaporated. The residue is crystallized from ether-hexane toafford 6-(1-hydroxyethyl)-6-methoxypenicillanic acid as a white,crystalline solid melting at 201°-204° C. with decomposition. To anethanol solution contaning the free acid is added 1 ml of a 0.6 Mdichloromethane solution of potassium 2-ethylhexanoate followed by 30 mlhexane. The precipitate is filtered, washed with hexane and dried invacuo at 50° C. to afford, as a white powder, potassium6-(1-hydroxyethyl)-6-methoxypenicillanate.

EXAMPLE 21

Activated mossy zinc (500 mg) and zinc dust (100 mg) are added to asolution of 2,2-dimethyl-3α-cyano-6α-bromopenam (522 mg, 2 mmol) andp-(2-tetrahydropyranyloxy)benzaldehyde (750 mg, 3.75 mmol) preparedaccording to E. Piers, W. deWaal and R. W. Britton, J. Am. Chem. Soc.,93, 5113 (1971) in 1 ml of dry tetrahydrofuran. After stirringvigorously at 50° for 3 hrs., the mixture is allowed to cool and 1 ml ofpH 5 phosphate buffer is added. After standing for 10 min., the solidsare removed by filtration and washed thoroughly with ethyl acetate. Thefiltrate is extracted with ethyl acetate. The combined extracts arewashed with phosphate buffer and saturated sodium chloride, dried withsodium sulfate and the solvents removed by evaporation. The crudematerial is purified by chromatography on 60 g of silica gel using 40%acetone/chloroform as eluant to afford 2,2-dimethyl-3α-cyanopenam as aby-product melting at 73°- 75° C. and a mixture of2,2-dimethyl-3α-cyano-6α-[p-(2-tetrahydropyranyloxy)-α-hydroxybenzyl]penamand2,2-dimethyl-3α-cyano-6β-[p-(2-tetrahydropyranyloxy)-α-hydroxybenzy]-penam.Separation of the 6α-and 6β-compounds is effected by PLC (10%acetone/toluene; two developments) providing the individual 6α- and6β-compounds.

EXAMPLE 22

2,2-Dimethyl-3α-cyano-6α-[p-(2-tetrahydropyranyloxy)-α-hydroxybenzyl]penam(45 mg, 0.12 mmol) is dissolved in 3 ml of acetone and 0.5 ml of 10%phosphoric acid. After stirring 18 hours at room temperature, thesolution is diluted with a 10 fold excess of ethyl acetate and washedwith saturated sodium chloride. Purification of the crude phenol (42 mg)by PLC (35% acetone/toluene) provides2,2-dimethyl-3α-cyano-6α-(p-hydroxy-α-hydroxybenzyl)penam.

The 6β-tetrahydropyranyl ether is deprotected in the same manner toprovide 2,2-dimethyl-3α-cyano-6α-(p-hydroxy-α-hydroxybenzyl)penam.

EXAMPLE 23

Activated mossy zinc (1.0 g) and zinc dust (1.2 g) is added to asolution of 2,2-dimethyl-3α-cyano-6α-bromopenam (1.0 g, 3.85 mmol) andp-diphenylmethoxycarbonylbenzaldehyde (1.96 g, 6.2 mmol) in 6 ml of THF(distilled from calcium hydride). After stirring vigorously at roomtemperature for 18 hours, the mixture is diluted with ethyl acetate.Phosphate buffer (pH 5, 5 ml) is then added. After stirring for 10 min.,the solids are removed by filtration and washed thoroughly with ethylacetate. The layers of the filtrate are separated and the organic phaseis washed with phosphate buffer and saturated sodium chloride. Dryingwith sodium sulfate and solvent removal provides a yellow foam.

Purification of the crude mixture on 60 g of silica gel 60 with 5%acetone/toluene as eluant affords2,2-dimethyl-3α-cyano-6α-(p-diphenylmethoxycarbonyl-α-hydroxybenzyl)penamand2,2-dimethyl-3α-cyano-6β-(p-diphenylmethoxycarbonyl-α-hydroxybenzyl)penam.

EXAMPLE 24

2,2-Dimethyl-3α-cyano-6α-(p-diphenylmethoxycarbonyl-α-hydroxybenzyl)penam(0.26 mmol, 132 mg) is dissolved in 1.2 ml of anisol and cooled to 0°.Dry trifluoroacetic acid (3 ml) is added and the solution is allowed tostand at 0° for 2 mins. The trifluoroacetic acid is removed under highvacuum at 0° and the anisol is distilled off at 30°. More anisol isadded and distilled off. This is again repeated and the oily residuepartitioned between 5 ml of cold water containing 22 mg of sodiumbicarbonate and ether. The phases are separated and the aqueous phase isagain washed with ether and lyophilized, affording sodium2,2-dimethyl-3α-cyano-6α-(p-carboxy-α-hydroxybenzyl)penam.

2,2-dimethyl-3α-cyano-6β-(p-diphenylmethoxycarbonyl-α-hydroxybenzyl)penam(62 mg, 0.12 mmol) is treated in the same manner to provide sodium2,2-dimethyl-3α-cyano-6β-(p-carboxy-α-hydroxybenzyl)penam.

What is claimed is:
 1. A compound of the formula: ##STR44## wherein Y issulfur or sulfoxide; R₁ together with the carbon atom to which it isattached, is the carbon residue of an aldehyde or ketone which containsno functional group that would preferentially react with a zinchalo-β-lactam intermediate over the oxo functionality; R₂ is a group ofthe formula

    --(CH.sub.2).sub.m --(X).sub.p --(CH.sub.2).sub.n --

wherein X is O or S; m is 0-3; p is 0-1; n is 0-3; and m+p+n is 3-5; andR₄ is cyano, or --COOR₁₁ wherein R₁₁ is a readily removableester-forming moiety, and the pharmaceutically acceptable acid additionsalts thereof.
 2. A compound of the formula: ##STR45## wherein R₁,together with the carbon atom to which it is attached, is the carbonresidue of an aldehyde or ketone which contains no functional group thatwould preferentially react with a zinc halo-β-lactam intermediate overthe oxo functionality;R₂ is a group of the formula:

    --(CH.sub.2).sub.m --(X).sub.p --(CH.sub.2).sub.n --

wherein X is O or S;m is 0-3; p is 0-1; n is 0-3; and m+p+n is 3-5; R₃is hydrogen or lower alkoxy; Y is sulfur or sulfoxide; R₁₂ is hydroxy,lower alkoxy, formyloxy, lower alkanoyloxy, lower alkylsulfonyloxy, or ahalogen atom; and R₁₃ is hydrogen, an alkali metal cation,acetoxymethyl, or a readily removable ester-forming moiety with theproviso that when R₁₂ is hydroxy, then R₁₃ is not a readily removableester-forming moiety, and the pharmaceutically acceptable acid additionsalts thereof.
 3. A compound according to claim 1 which is benzylspiro-[3'-hydroxy oxacyclopenyl]-2',6α-penicillanate.
 4. A compoundaccording to claim 1 which is benzyl spiro-[3'-hydroxyoxacyclopentyl]-2',6β-penicillanate.